1. Field of the Invention
The present invention relates to anionic/cationic surfactant mixtures. More particularly, the present invention relates to the use of water-soluble complexes of anionic and cationic surfactants as superior oily soil removal agents.
2. Description of the Prior Art
In principle any surfactant can be used in detergency. In practice, however, only anionic and nonionic surfactants are used. Cationic surfactants (specifically the quaternary ammonium salts) when used in heavy duty liquid detergents, decrease detergency and enhance soil redeposition. Consequently, there is a general notion that anionic and cationic surfactants cannot be used in the same formula without loss of efficacy. On the other hand, cationic surfactants are one of the most important class of compounds used as antistat and softening agents in rinse cycle products. And recently, they have been used in heavy duty laundry detergent-softener products. Softening is achieved in such products but unfortunately at the expense of cleaning efficacy. Cationic surfactants are also the main ingredients in hair conditioners. Unfortunately, here also there is a problem attributed to the presence of quat. A residue build-up accumulates on the hair due to extended use of conditioners. Consumers are believed to be aware of the problem and try to overcome it by changing shampoos occasionally.
Numerous attempts to overcome the aforementioned problems have been tried. Illustrative of these attempts are:
U.S. Pat. No. 3,703,480, to Grant et al., discloses a washing cycle fabric softener consisting essentially of a cationic quaternary ammonium fabric softener and an amino polyureylene resin. In particular, it is noted that quaternary ammonium softener compounds are positively charged and deposit readily on a negatively charged surface of textiles to form a lubricous surface on the textile which feels soft to the touch. However, it is also noted that a large percentage of the common laundry detergents contain anionic surface active agents which tend to inactivate or neutralize cationic softening agents. The inclusion of the amino polyureylene resin in combination with the quaternary ammonium softener compounds is taught to substantially reduce this problem of incompatibility of anionics and cationics.
U.S. Pat. No. 3,730,912, to Inamorato, discloses a ternary foam control system comprising a synergistic mixture of a fatty acid, polyethoxylated quaternary ammonium salt and a high molecular weight amide or a primary, secondary or tertiary amine. The ternary foam control system may be used in conjunction with conventional useful detergents including anionic detergents such as alkyl-benzene sulfonic acid and its salts, alkali metal dialkyl sulfosuccinates, alkali metal alkyl sulfates, sodium diisopropylnaphthalenesulfonate, sodium octylphenoxyethoxyethylsulfonate, etc. The ternary foam control system broadly comprises about 20 to 80 percent fatty acid, about 10 to 60 percent polyethoxylated quaternary ammonium salt and about 10 to 60 percent amide or amine. In a total detergent system, there is employed broadly about 1 to 6 percent fatty acid, about 1 to 6 percent polyethoxylated quaternary ammonium salt and about 1 to 6 percent amide or amine, in conjunction with about 8 to 18 percent of anionic detergent.
U.S. Pat. No. 3,997,453, to Wixon, discloses stable, fabric softening compositions having improved dispersibility in cold water which comprise a cationic quaternary ammonium softener as the sole fabric softening agent and an organic, anionic sulfonate. The weight ratio of the cationic softener to the anionic sulfonate may be from about 80:1 to 3:1. The compositions typically comprise 0.4 to 5% of the anionic sulfonate detergent and from about 6 to about 25% of the cationic softener material, with the balance being primarily water. The amount of organic anionic sulfonate additive is insufficient to cause significant loss of softening performance due to cationic-anionic interaction.
U.S. Pat. No. 4,000,077, to Wixon, discloses a softening composition which imparts a superior degree of softness and whiteness to textiles and which contains, as the essential ingredients, a cationic quaternary softener, preferably an imidazolinium salt, and a minor amount of a higher aliphatic alcohol sulfate. The weight ratio of the cationic quaternary softener to the higher alcohol sulfate may be from 10:1 to 2:1. The softening composition may be prepared, and used, in liquid or solid form, adsorbed onto a carrier. The amount of the cationic quaternary softener present in the liquid composition may be within the range of 2-20%. The liquid composition may be sprayed on, or otherwise agglomerated with, particles of borax, sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, sodium sulfate, sodium chloride, phosphate salts, or other carrier materials to form granular or powdered compositions. These solid compositions may contain the cationic quaternary softener in an amount within the range of 2-30%.
U.S. Pat. No. 4,298,480, to Wixon, discloses heavy-duty detergent compositions, for imparting improved softness and detersive effects to fabrics laundered therewith, which compositions include, in addition to conventional builder and principally anionic surfactant components, fatty acid soap and cationic softener of the di-lower-di-higher alkyl quaternary ammonium and/or heterocyclic imide type, e.g., imidazolinium. The weight ratio of soap to softener is about 8:1 to 1:3, preferably about unity. The soap, in the form of a spaghetti, flake or other shape, is present in the product composition as substantially homogeneously dispersed, discrete particles.
U.S. Pat. No. 4,329,237, to Wixon, discloses heavy-duty detergent compositions, for imparting improved softness and detersive effects of fabrics laundered therewith, which compositions include, in addition to conventional builder and principally anionic surfactant components, cationic softener of the all-lower-all-higher alkyl quaternary ammonium- and/or heterocyclic imide-type and a mixture of fatty acid soap and nonionic organic surfactant. The weight ratio of soap to softener is about 8:1 to 1:3, preferably about unity. The soap/nonionic surfactant mixture, in the form of a spaghetti, flake or other shape, is present in the product composition as substantially homogeneously dispersed discrete particles.
U.S. Pat. No. 4,411,803, to Wixon, discloses heavy-duty detergent compositions, for imparting improved softness and detersive effects to fabrics laundered therewith, which compositions include, in addition to conventional builder and principally anionic surfactant components, cationic softeners of the di-lower-di-higher alkyl quaternary ammonium- and/or heterocyclic imide-type and a mixture of fatty acid soap and nonionic organic surfactant. The weight ratio of soap to softener is about 8:1 to 1:3, preferably about unity. The soap/nonionic surfactant, in the form of a spaghetti, flake or other shape, is present in the product composition as substantially homogeneously dispersed, discrete particles.
U.S. Pat. No. 4,450,085, to Wixon, discloses heavy-duty detergent compositions, for imparting improved softness and detersive effects to fabrics laundered therewith, which compositions include, in addition to conventional builder and principally anionic surfactant components, cationic softeners of the di-lower-di-higher alkyl quaternary ammonium- and/or heterocyclic imide-type and a mixture of fatty acid soap, nonionic organic surfactant and magnesium sulfate. The weight ratio of soap to softener is about 8:1 to 1:3, preferably about unity. The soap/nonionic surfactant/magnesium sulfate mixture, in the form of a spaghetti, flake or other shape, is present in the product composition as substantially homogeneously dispersed, discrete particles.
U.S. Pat. No. 3,869,412, to Waag, discloses surface-active compositions having controlled foaming properties comprising an anionic sulphonate or sulphate ester surfactant; a nonionic polyoxyalkylene ether, ester or glycol surfactant; and an anionic polyoxyalkylene phosphate ester surfactant. The polyoxyalkylene phosphate ester and the polyoxyalkylene ether, ester or glycol surfactants serve as low-foaming components, and the anionic sulphonate or sulphate ester surfactant increases the foaming properties of the mixtures in proportion to the amount present.
U.S. Pat. No. 3,956,198, to Bauer, discloses a washing-aid composition, suitable for the removal of stains and soil from delicate fabrics which are deleteriously affected by alkaline conditions, comprising: a phosphate ester surfactant; an alkali metal salt of an aminopolyacetic acid in an amount sufficient to essentially neutralize the surfactant to a pH of about 7; a water-miscible organic solvent in an amount sufficient to solubilize organic borne stains and dirt; and water in an amount sufficient to solubilize the aminopolyacetic acid salt.
U.S. Pat. No. 4,116,885, to Derstadt, discloses detergent compositions, which are particularly effective in removing oily soils from hydrophobic fibers, comprising specific anionic surface-active agents, polyester soil-release polymers, and limited amounts of incompatible anionic surface-active agents. Co-surfactants such as sulfobetaines and nonionics may also be included in the compositions.
U.S. Pat. No. 4,132,680, to Nicol, discloses detergent compositions which are particularly suitable for providing hydrophobic fabrics, such as polyester, with a soil release effect for oily soils. The compositions contain surface-active agents (anionic, nonionic, ampholytic, zwitterionic and mixtures thereof), polyester soil-release polymers and a component which dissociates in aqueous solution to produce quaternary ammonium cations.
U.S. Pat. No. 4,137,190, to Chakrabarti et al., discloses a detergent composition comprising a low-foaming, non-ionic surfactant and a synergistic hydrotrope mixture. The hydrotrope mixture is composed of two classes of organic phosphate esters, the first class is a reaction product of a compound of the formula (i) EQU R(OCH.sub.2 CH.sub.2).sub.n OH, (i)
wherein R is alkyl, aryl, aralkyl, or alkaryl and n is 1 to 10, with phosphorous pentoxide, and the second class is a reaction product of a compound of the aforementioned formula (i) with polyphosphoric acid. The weight ratio of the first class to the second class is 1:9 to 9:1.
U.S. Pat. No. 4,247,424, to Kuzel et al., discloses stable liquid detergent compositions which contain an ethoxylated alcohol or ethoxylated alkylphenol nonionic surfactant, an amine oxide surfactant, a water-soluble detergency builder, a hydrophobic emulsifier and water.
U.S. Pat. No. 4,264,457, to Beeks et al., discloses a cationic liguid laundry detergent for softening fabrics and giving them antistatic properties. The detergent contains: about 3-35 weight % nonionic surfactant formed by reacting 5-200 moles of ethylene oxide with a hydrophobic organic compound having 8-50 carbon atoms; about 3-30 weight % mono-long-chain cationic surfactant; and water-soluble anionic surfactants selected from a mixture of C.sub.4-10 alcohol sulfates and C.sub.12-22 alcohol ethoxylated ether sulfates or carboxylate. The anionic surfactants are present at a mole ratio of about 1:5 to 5:1. The mole ratio of cationic surfactant to anionic surfactant is about 0.8:1 to 10:1.
U.S. Pat. No. 4,348,305, to Henneman et al., discloses a stable, liquid detergent with fabric softening action for simultaneously washing and softening delicate fabrics. The detergent composition comprises: (a) from about 5 to 18 weight of a mixture of alkyl polyglycol ethers of the formula ##STR1## wherein R.sup.1 represents a linear alkyl radical,
R.sup.2, in from about 20 to 75% of said alkyl polyglycol ethers, represents a C.sub.1-4 alkyl group and, in from about 25 to 80% of said alkyl polyglycol ethers, represents a hydrogen atom, PA1 the total number of carbon atoms in R.sup.1 and R.sup.2 together being from about 11 to 15, and PA1 n represents an average value of from about 5 to 9; (b) from about 5 to 18 weight % of a mixture of alkyl polyglycol ethers of the formula ##STR2## wherein R.sup.1 represents a linear alkyl group, PA1 R.sup.2 is a hydrogen atom or, in from about 20 to 75% of said alkyl polyglycol ethers, represents a C.sub.1-4 alkyl group and, in from about 25 to 80% of said alkyl polyglycol ethers, represents a hydrogen atom, PA1 the total number of carbon atoms in R.sup.1 and R.sup.2 together being from about 6 to 10, and PA1 n represents an average value of from about 3 to 8; and (c) from about 2.5 to 10 weight % of a fabric-softening quaternary ammonium salt. The quantitative ratio of components (a) and (b) is from about 2:1 to 1:2. PA1 (A) from 10 to 60 weight % of one or more phosphoric ester surfactants represented by the formulae ##STR3## where each of R.sub.1, R.sub.2 and R.sub.3 represents a saturated or unsaturated hydrocarbon group having from 8 to 18 carbon atoms, PA1 each A and B represents a hydrogen atom, an alkali metal, ammonium or an alkanol amine having 2-3 carbon atoms, and PA1 each of 1, m and n is 0 or an integer of from 1 to 10, PA1 (B) from 0.5 to 15 weight % of an organic or inorganic salt, PA1 (C) from 0.5 to 15 weight % of polyethylene glycol having a molecular weight of from 4,000 to 10,000, and PA1 (D) a surface active agent selected from the group consisting of PA1 R.sub.2 is an alkyl group of not more than 6 carbon atoms, PA1 R.sub.3 and R.sub.4, which may be the same or different, are selected from the group consisting of alkyl of not more than 6 carbon atoms and --R.sub.5 O).sub.n H, wherein R.sub.5 is an alkylene of 2 to 4 carbon atoms and n is a number of from 1 to 25, and PA1 X.sup.- is a water-soluble anion. PA1 R.sub.8 is a straight chain or branched, saturated or unsaturated aliphatic radical of from about 8 to about 22 carbon atoms, PA1 R.sub.9 is a hydrocarbon radical of from about 8 to about 22 carbon atoms, PA1 R.sub.5 is an alkylene of 2 to 4 carbon atoms, PA1 m is a number of from 1 to 25, and PA1 m' is a number of from 0 to 25, PA1 M is a water-soluble cation; PA1 R.sub.11 is R.sub.12 --O(R.sub.5 O).sub.o or --OM, PA1 R.sub.5 is an alkylene of 2 to 4 carbon atoms, PA1 o is a number of 1 to 25, PA1 R.sub.12 is a hydrocarbon radical of from about 8 to about 22 carbon atoms, and PA1 M is a water-soluble cation; PA1 M is a water-soluble cation.
U.S. Pat. No. 4,369,134, to Deguchi, discloses a creamy cleansing composition comprising:
(1) from 0.1 to 15 weight % of an ethylene oxide addition type non-ionic surface active agent, PA2 (2) from 0.05 to 10 weight % of a cationic surface active agent represented by the formula ##STR4## where R.sub.4 represents a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, PA2 R.sub.5 represents a methyl group or an ethyl group, PA2 X represents a halogen atom, and PA2 each of p and q represents an integer of from 1 to 15, and PA2 (3) from 0.05 to 10 weight % of a cationic surface active agent represented by the general formula ##STR5## where R.sub.6 represents a methyl group or an ethyl group, R.sub.7 represents a saturated or unsaturated hydrocarbon group having from 8 to 18 carbon atoms, and
R.sub.4, R.sub.5 and X are as defined above.
U.S. Pat. No. 4,436,653, to Jacobson et al., discloses stable liquid detergent compositions containing nonionic, amine oxide and alcohol polyethoxylate sulfate surfactants and a water-soluble detergency builder. The compositions are single phase isotropic liquids which exhibit improved freeze-thaw stability. The polyethoxylate sulfate surfactant enhances detergency performance on textiles that have been softened with a conventional cationic fabric softener.
U.S. Pat. No. 4,493,782, to Williamson, discloses cleansing compositions comprising 90-95 weight % of monoesters of phosphoric acid having the formula ##STR6## wherein n has a value from about 7 to 11 and m has a value from about 2 to 4; and 2-3 weight % of a stabilizer having the formula ##STR7##
U.S. Pat. No. 4,715,990, to Crossin, discloses a soil-release promoting, enzyme-containing nonionic detergent, in the form of a transparent or translucent liquid, comprising: a synthetic organic nonionic detergent; a higher fatty alcohol polyethoxylate sulfate; a soil-release promoting polymer of polyethylene terephthalate and polyoxyethylene terephthalate; a proteinaceous and/or amylaceous soil enzymatically hydrolyzing effective amount of enzyme(s); an enzyme stabilizer; and an aqueous medium.
U.S. Pat. No. 3,892,669, to Rapisarda et al., discloses a clear, homogeneous, aqueous fabric-softening composition comprising a solubilized tetralkyl quaternary ammonium salt having two short-chain alkyl groups and two long-chain alkyl groups. The solubilizers comprise aryl sulfonates, diols, ethers, low molecular weight quaternaries, sulfobetaines, alkyl taurines, amines, phosphines, sulfoxides and nonionic surfactants.
U.S. Pat. No. 4,058,489, to Hellsten, discloses a detergent composition having good cleaning effectiveness while simultaneously imparting a soft feel and/or a good conductivity for static electricity to the material treated therewith. The composition comprises a mixture of surfactants of which: (a) from 30 to 90% by weight is a surfactant selected from the group consisting of nonionic surfactants, amphoteric surfactants and mixtures thereof; and (b) from 10 to 70% by weight is a surfactant mixture comprising at least one anionic surfactant and at least one cationic surfactant in a charge ratio (anionic surfactant:cationic surfactant) within the range from about 0.60 to about 0.90.
U.S. Pat. No. 4,118,327, to Seugnet, discloses fabric softener/anti-static compositions wherein phosphoric acid esters, which are anionic anti-static agents, are incorporated into conventional cationic fabric softeners for addition to the rinse cycle of automatic home laundry machines or for the final rinse in an industrial fabric treating process.
U.S. Pat. No. 4,222,905, to Cockrell, Jr., discloses a laundry detergent composition containing no or low levels of phosphate materials. The compositions are unusually effective in removing particulate soils from fabrics. The compositions comprise from about 5 to about 100% by weight of a surfactant mixture consisting essentially of (a) a biodegradable nonionic having the formula EQU R(OC.sub.2 H.sub.4).sub.n OH
wherein R is a primary or secondary alkyl chain of from about 8 to 22 carbon atoms and n is an average of from about 2 to about 12; and (b) a cationic surfactant, free of hydrazinium groups.
U.S. Pat. No. 4,292,035, to Battrell, discloses fabric softening compositions comprising a combination of an anionic surfactant and a complex of certain smectite clays with certain organic amines and certain quaternary compounds.
U.S. Pat. No. 4,333,862, to Smith et al., discloses a liquid detergent composition comprising from 2 to 100% of a surfactant system consisting essentially of a water-soluble or water-dispersible combination of (a) from 15 to 45% of an anionic surfactant; (b) a water-soluble quaternary ammonium cationic surfactant, in a ratio of anionic:cationic of less than 5:1; and (c) a nonionic surfactant having the formula RO(C.sub.2 H.sub.4 O).sub.n H wherein R is a primary or secondary, branched or unbranched C.sub.8-24 alkyl or alkenyl or C.sub.6-12 alkyl phenyl, and n, the average degree of ethoxylation, is from 2 to 9, wherein the ratio of nonionic:cationic surfactant is from 5:1 to 2:3.
U.S. Pat. No. 4,338,204, to Spadini et al., discloses a laundry detergent composition providing cleaning and softening of textiles. The composition comprises: an anionic surfactant; a water-insoluble di-C.sub.10-26 tertiary amine; and a water-soluble cationic compound which may be a mono C.sub.10-18 alkyl, primary, secondary or tertiary amine, or a water-soluble salt thereof or a water-soluble mono C.sub.8-16 alkyl quaternary ammonium compound.
U.S. Pat. No. 4,632,530, to Gross et al., discloses dyeing auxiliaries comprising (A) 10 parts by weight of an anionic product obtained by addition of 5 to 20 mols of ethylene oxide to an aliphatic saturated or unsaturated alcohol of 10 to 24 carbon atoms, followed by carboxymethylation; (B) 1 to 15 parts by weight of a cationic addition product of 50 to 150 mols of ethylene oxide to a fatty amino-C.sub.2-3 -alkylene-amine; (C) 1 to 10 parts by weight of a nonionic addition product of 20 to 150 mols of ethylene oxide to castor oil, or a non ionic sequenced addition product of 20 to 150 mols of ethylene oxide and 1 to 10 mols of propylene oxide to castor oil; and (D) 1 to 20 parts by weight of a N-(.beta.-hydroxy-C.sub.2-4 -alkyl)-fatty acid amide.
U.S. Published patent application Ser. No. B 310,740, to Barrat, discloses a detergent composition containing enzymes consisting essentially of: (a) from 0.001% to about 5% by weight of a proteolytic enzyme having an iso-electric point greater than 9.5 selected from the group consisting of the enzymes produced by Bacillus alcalophilus NCIB 8772 and bacterium strain NCIB 10147; (b) from about 20% to about 80% by weight of a cationic surfactant; and (c) from about 80% to about 20% by weight of an anionic surfactant.
Canadian Patent 818,419, to Urfer et al., discloses a textile softener/detergent composition comprising: a cationic-anionic electro-neutral complex; and a quantity of a cationic-nonionic dispersing mixture sufficient to effectively disperse the electro-neutral complex in an aqueous medium, and to effectively maintain tile dispersion in an environment which will inhibit interfering anionic materials from altering the composition's capability for simultaneously washing and softening textiles.
Additionally, there have been many studies and symposia (e.g., Scamehorn, J. F., ed., "Phenomena in Mixed Surfactant Systems", ACS Symposium Series 311, Washington, D.C. (1986)) on mixed surfactant systems. The effect of alkyl groups and oxyethylene groups in nonionic surfactants on the surface tension of anionic-nonionic systems have been described (Abe et al., J. Colloid Interface Sci., 107, p. 503 (1985); Ogino et al., J. Colloid Interface Sci., 107, p. 509 (1985); and Rosen et al., J. Colloid Interface Sci., 95, 443 (1983)). Interaction between betaines and cationic surfactants (surface tension vs. concentration) has also been studied (Zhu et al., J. Colloid Interface Sci., 108, 423 (1985)).
Mixed surfactant systems have shown synergistic effects relative to the properties of their individual surfactant components. Synergism increased with the degree of charge difference. Synergism between anionic and anionic or nonionic and nonionic is less than anionic and nonionic or cationic and nonionic which in turn are much less than those of anionic and cationic mixtures (Rosen et al. in "Phenomena in Mixed Surfactant Systems" (Scamehorn, J. F., ed.), ACS Symposium Series 311, Washington, D.C. (1986), pp. 144-162; and Zhao et al. in "Phenomena in Mixed Surfactant Systems" (Scamehorn, J. F., ed.) ACS Symposium Series 311, Washington, D.C. (1986) pp. 184-198).
Studies on anionic/cationic systems are recent and few compared to studies on other mixed surfactant systems. However, strong synergism has been exhibited by these systems. Surface activity, particularly the critical micelle concentration (cmc), surface tension, and microemulsion behavior (Bourrel et al., Tenside Detergents, 21, 311 (1984)), were the most studied properties. For example, the surface activities of mixed aqueous solutions of sodium dihexylsulfosuccinate with dioctyl(hydroxyethyl)methylammonium chloride and sodium dihexylsulfosuccinate with octyl(hydroxyethyl)dimethylammonium chloride were much higher than those of the single surfactants (Zao, G., Huoxue Xuebo, 43, 705 (1985) (Ch. Chem. Abstracts 103:184033n)). The strong synergistic effect on surface pressure for mixed solutions of cationic and anionic surfactants has been studied quantitatively. When dilute solutions of sodium dodecylsulfate and dodecyltrimethylammonium bromide were mixed, tile surface pressure increased by more than 40 mN/m. Also, the cmc and the minimum surface tension were lower for the mixture than for either the anionic or cationic surfactants alone (Lucassen-Reynders et al., J. Colloid Interface Sci., 81, p. 150 (1981)).
Mixed anionic/cationic systems have shown not only synergistic but also antagonistic effects relative to the properties of the individual surfactant components (Chobanu et al., Izv. Akad. Nauk. Mold. SSR, Ser. Biol. Khim. Nauk., 5, p. 66 (1982)). Unlike the other mixed surfactant systems, most anionic/cationic surfactant mixtures studied are insoluble or only slightly soluble. Therefore, their practical use, in areas where high concentration of surfactants are needed, is very limited.